What are Electric Fence Insulators

Electric fence insulators are non-conductive devices that are used to secure the wire of the fence to the metal posts, while making sure that the electrical current isn’t given a convenient path to ground through the metal poles. Electric fence insulators are available in different materials and different sizes, each of which is used for a different type of application. Some are not meant to be used with high voltage levels. And then some are not designed to be used for fences electrified with alternating current.  The paragraphs below contain information regarding construction materials and sizes of electric fence insulators.

Materials Used in Construction

Technically speaking, anything that won’t conduct electricity can be used as an electric fence insulator. However, some materials are used more than others because they last longer, are easier to use, easier to make or they have better insulating properties. For lower voltage fences, rubber, plastics and even wood can and has been used for insulating materials. In higher voltage fences, ceramic is the construction material of choice for a number of reasons. The most important reason ceramic is preferred is that it has better insulating qualities in all conditions. The other main reason that ceramic is used more than any other material is its durability and resistance to heat. Over time and with exposure to the elements on a constant basis, materials such as rubber and wood can and will degrade and break down, eventually failing and falling apart. Electric fence insulators made of high quality ceramic will last for many years.

Voltage Determines Size

Electrical current will jump a gap in order to make its way to ground, if doing so is the path of least resistance. Your car’s ignition system uses this fact to create the spark needed to ignite the air fuel mixture. The higher the voltage and current combination being supplied, the larger the gap it will be able to jump. A good rule of thumb is that for every one hundred volts supplied, at one ampere of current, you should have at least a half inch of insulator size separating the current carrying wires from a path to ground, such as a metal fence pole. Environmental conditions such as amount of rain normally expected as well as relative humidity will also need to be taken into account. If it rains heavily or your area experiences high relative humidity, you should add at least one inch to the insulators that you purchase for your electric fence.


There are a number of designs or styles of electrical insulators. Most are white ceramic and have a screw embedded on opposite ends of the insulator. One is used to mount the insulator and the other is used to secure the electrified wire to the insulator. Some insulators are nothing more than rods made of an insulating material. The most common style of insulator looks like mushrooms stacked on top of each other.

If you’re planning on building or upgrading an electric fence, you’re going to need electric fence insulators. The information provided in the above paragraphs was given so as to assist you in knowing why you need them and the relationship between size and voltage.